Can chewing gum actually make people smarter? British researchers believe so. A recent study (Scholey 2000; 2001) conducted by the University of Northumbria and the Cognitive Research Unit in England found that the act of chewing gum actually improves short- and long term memory by up to 35 percent.

The results are a far cry from the days when chewing gum was said to be unhealthy. In 1869, one doctor wrote that chewing gum would exhaust the salivary glands and cause the intestines to stick together!

The study (ibid) tested a group of seventy-five individuals split into three groups—actual chewers, pretend chewers, and non-chewers (the control). Subjects were tested for short-term memory after the two chewing groups spent three minutes chewing their real or imaginary gum. The heart rate of the actual chewers was measured to be three beats

faster per minute than the non-chewers, and 1.5 beats per minute faster than the pretend chewers. One interpretation of the results is that a mild increase in heart rate may improve the delivery of oxygen and glucose to the brain enough to improve cognitive function.

The tests included questions that related to short-term memory, such as recalling words and pictures, and working memory, such as being able to remember a person's telephone number.

Scholey, who presented the team’s findings to a symposium at the British Psychological Society's annual conference in April, said the improved performance in a range of memory tests might be "attributable to an increase in heart rate coupled with a surge in insulin to the brain due to mouthwatering in anticipation of a meal." We know the brain contains receptors for insulin—molecular docking points that bind onto the insulin molecule. Although their function isn't well known, "we do know insulin receptors are densely packed in the hippocampus which is crucial for memory," said the researcher.

In another study that examined the relationship between chewing and memory, Japanese scientists found that chewing stimulated signals in the learning center of the brain (Onozuka 1999; 2000). Thus, chewing anything, including gum, may help memory function. Onozuka and his team used magnetic resonance imaging (MRI) to study the brain activity of humans while they were chewing. They found that the jaw movements increased signals in the hippocampus area of the brain—an area that stores information before moving on to long-term memory or purging.

As we age, hippocampal cells start to deteriorate and short-term memory gets worse. Elderly people with missing teeth often chew less, too, and some studies have suggested that bad memory and tooth loss may be linked.

The findings suggest that chewing is essential to preserve the ability to form memories in old age. It’s also possible that chewing may improve our memories by reducing stress. The hippocampus helps control levels of stress hormones in the blood. So if older people chew less, their stress levels might rise enough to cause a decline in short-term memory.